Synthesis of oligosaccharides by using solid-phase method and hybrid method of solid-phase and liquid-phase

点击翻译按钮获取中文摘要

Efficient synthesis of oligosaccharides by using solid-phase method and hybrid method of solid-phase and liquid-phase was investigated. We previously established "Chemical Fishing" method, where desired compound having azide function is selectively fished out of the reaction mixture by using the specific reaction between solid-supported phosphine and azide. This method was applied to the solid-phase synthesis of the elicitor pentasaccharide. Synthetic study of N-linked oligosaccharide of glycoprotein was also investigated. We developed a novel method for cleavage of trichloroethoxycarbonyl(Troc) group by radical reaction using (Bu_3Sn)_2. This method was then applied to solid-phase synthesis and rendered the use of Troc group for stereocontrolled β-glucosaminilation on solid-support by using its neighboring group participation effect. Stereoselective β-mannosylation was effected by using 4,6-O-benzylidene mannnosyl N-phenyltrifluoroacetimidate as a glycosyl donor and TMSOTf as an acid catalyst(α:β=1:9). We also established α-selective sialylation by using N-phthaloyl sialic acid phenyltrifluoroacetimidate as a donor and TMSOTf as an acid catalyst.We previously reported Synthesis based on affinity separation(SAS), where desired compound having a tag moiety is rapidly separated from a reaction mixture by using specific affinity between the tag and the molecule that recognizes the tag. In the present study, we developed the new SAS method using the interaction between podand ether tag and solid-supported ammonium ion. The present method was applied to the rapid synthesis of small oligosaccharide library including Lewis X. Various partial structures and analogues of immunostimulating glycoconjugate lipopolysaccharide and peptidoglycan were synthesized in order to elucidate their biological functions.